Daphne Alce fled political upheaval and an abusive husband in Haiti. Then she ran from a boyfriend who beat her in Canada and tried to make her way to Philadelphia, where she had sent her children to live with a sister. When Alce tried to cross the US border with a fraudulent passport in October, she was caught and arrested.

US prosecutors, hearing her story, dropped the charges. An asylum officer interviewed her and determined she had a credible fear of persecution if she were deported to Haiti. But immigration officials kept her
in jail, holding her in Boston and releasing her only last month after the Globe requested an interview.

“I was crying, crying, crying,” Alce said after a brown minivan dropped her off at South Station one day last month, still dressed in a gray prison sweatsuit and white sneakers. “They were just holding me here for no reason.”

Despite the high-profile release of hundreds of immigrants this week, immigration lawyers and advocacy groups say that thousands of immigrants like Alce — who have no criminal record and pose no threat to their communities — remain jailed by the nation’s sprawling immigration system, sometimes for prolonged periods.

The detainees are held for many reasons, but often they are merely awaiting a hearing before an immigration judge or waging an appeal, and lawyers say immigration officials instead should release them to their families.

Critics say detention is necessary to ensure that illegal immigrants are deported, but advocates argue that many of the roughly 30,000 detainees could be monitored in cheaper and more humane ways.

“We think that most people that are in detention right now can be let out,” said Laura Rotolo, staff attorney with the American Civil Liberties Union of Massachusetts. “Until now we have not gotten the sense that the administration was willing to do that.”

‘We think that most people that are in detention right now can be let out.’

Immigrant advocates have pushed for years for the release of such detainees, without much success. Even a directive in 2011 asking Immigration and Customs Enforcement officers to focus resources on criminals and others considered priority cases did not result in major releases, advocates said.

But advocates recently began stepping up pressure on the Obama administration, seeing a prime political opportunity as the president and Congress attempt to hammer out legislation that could clear the way to legal status for some 11 million illegal immigrants nationwide.

Bill Greene/Globe Staff

Daphne Alce looked over paperwork at South Station before she boarded a bus to New York following her release from immigration detention in Boston.

The effort worries critics like Bristol County Sheriff Thomas Hodgson, whose agency detains immigrants for ICE. He said immigration officials should enforce the law unless it changes.

“We can’t keep marginalizing what the enforcement of our law is,” he said. “If everybody starts interpreting what their impression of the law ought to be, then we’re going to have problems with our democracy.”

This week, federal immigration officials, citing anticipated budget cuts forced by sequestration, released several hundred immigrants from jails across the United States. It ignited a political firestorm, cheering advocates but angering members of Congress and others who said the mass release could derail their efforts to craft immigration reform legislation.

Officials would not say if any immigrants were released in Massachusetts, but Suffolk and Bristol county jails said they were unaware of any sudden declines in the number of immigrant detainees.

Gillian Christensen, ICE spokeswoman, said immigration officials will keep trying to deport the released immigrants and has placed them on less costly forms of supervision to make sure the agency stays within budget. “All of these individuals remain in removal proceedings,” she said. “Priority for detention remains on serious criminal offenders and other individuals who pose a significant threat to public safety.”

Immigration advocacy groups, while heartened by the release, say they’ll continue to press for more.

Among those still detained this week was Ronei Ferreira-De Souza, a 36-year-old landscaper from Brazil who has been fighting to overturn a deportation order for five months from Plymouth County jail.

His lawyer, George Maroun, said Ferreira-De Souza is a church-going married man and the father of two US citizens with a stack of reference letters from friends who praise his work ethic and faith. And, his lawyer said, he has no criminal record, though he was once arrested for driving without a license.

“I don’t know why he’s in jail. It doesn’t follow any of the guidelines that they have,” said Maroun, based in Woburn. “He’s a father of two kids. He’s not a terrorist.”

An ICE spokesman said that Ferreira-De Souza has a final order of deportation from a judge and they are trying to return him to his homeland.

Alce’s lawyer, Thomas Griffin, said federal law enforcement is supposed to be flexible so that the law is enforced fairly. For instance, he said, prosecutors dropped criminal charges against her for having a fake passport in part because of her circumstances and her lack of a prior criminal record.

“She should have been treated not like a criminal committing a crime but like a person fleeing persecution. That’s what she was,” he said.

Alce said she knew she broke the law but she did not understand why immigration officers kept her in jail after prosecutors dropped the charges and she passed her asylum interview. At night she slept fitfully as mice skittered through the cells. She wept so often for her children, a 12-year-old daughter and a son who turned 3 while she was in jail, that others worried for her health. “It was awful,” she said.

She said she and her lawyer asked ICE agent Joseph Gilbert to let her return to her children, but she heard nothing until the Globe asked for an interview. Less than 24 hours later, they whisked her to South Station.

Alce was overjoyed, but her family reunion had to wait even longer.

She had no photo identification, so Amtrak refused to sell her a train ticket, the quickest way home. She took a deep breath and walked to the bus station and bought the fastest one-way ticket she could find.